Alkaline dry cell



March l0, 1953 s. RUBEN 2,631,181

ALKALINE DRY CELL Filed NOV.. 16, 1948 STEEL l@ f 1N VEN TOR. Jamai! /uifelz BY Patented Mar. 10, 1953 y y U NITED S TATEJS PATE NT (D FFI-CE .ALKALINE DRY'CELL.

Samuel -Ruben,New Rochelle, lSLY.

Application November 16, 1948, Serial'No.` 60,265

( Cl. :13G-111) 6f Claims'- 1 This invention `relates to "electrochemical cells for the generation and storagev of electrical 'energy and, more particularly 'to an alkaline dry cell dfnovel and improved character.

' my U. S. Paten-t 2;'42'23045, relating t'o analkaline dry cell, vthere is disclosed a sealed' 'alkaline primary cell having an amalgama-ted vz'i'nc anode: a cathode formed of 'a conductive body containing an electrolytically reducibl'e oxygen-- yielding'compound (such as mercuric or silver oxide) and an immobilized electrolyte comprising -anaq-ueous solution of an `alkali metal hydroxide f(such aspotassium hydroxide) containine;afsulostantial quantityof alkali metal'zincate. Thefpresence o'f'the zincate inthe electrolyte, in combina-tion with other features described inthe said patent, -presents 'or `strongly inhibits any tendency for a chem-ical hydrogen-generating reaction -(Ziz-|'--2H+ Zn++-l-H2') yto ltake place between the electrolyte and the zinc anode when theme11V is stored-prior to use as 'Well'.as during active use. These' factors have made possi-ble -a sealed alkaline vdry cell which does not genera-tev appreciable gas or leak electrolyte during' 'shelf life or `when Ainuse.

In myv co-pending application Serial No. 466,386',i filed December 9, 1942, now Patent No. 2.4631365' dated March 8, i949v andin-myco-pending application Serial No. 752,857', v`iiled .Tune 6; 1947', Vnow :Patenti No. 2,536,699 dated January `2', 19'5I,I"h'ave disclosed and claimed a primary cell comprising ajpair 'ofj electrodes anda 'solid crystalline alkaline electrolyte interposed between` and in 'contact withV said electrodes;

In my ico-pending application Serial No'. 671`,200,.l'ed May'21, 1946, I have disclosed'and claimed. a vdryA 4primarycell of at .or button-like constructioncomprising an Vanode of' compressed' metal powder and anv electrolyte element for'the cell which maybe formed of an aqueous alkaline Solution which `is" immobilized' by a kcompatible addition agent, preferably a material which con-- verts the; electrolyte into a gel, such as sodium* carboxy-methyl cellulose.

VIn my co-p'ending application Serial No; 682,734", filed July 11; 1946', novvV Patent` No; 2,542,575 dated February 20 1951-, -I `'have disclosed andv `claimed alkaline dry cells Vcomprising' an amalgamated zinc anode, Ya pressed cathodedepolarizer body, and a body lofy alkaline electrolyt'e gelinterposed4 between said anode and cathode. Preferablythe zinc anode is surrounded by and is in contactwith 'al cell' container. form-ed of atmetalinert to the electrolyte and having va `low contact potential to zinc. The' quantity of zinc inthe anode Vis .balanced with thedepolariging, capacity .of the cathodefso `that* bothanode and cathode :are consumed substantially simultaneously. In practice, a slight-excess of oxideis used When such a, cell combination is employed` with-an alkaline electrolyte. This; makes possible the-provision of a sealed alkaline dry cell which is `iree lof any tendency tov electrolyte leakage-or appreciable gas generation during shelf` life, cur-Y rentI generating life and ateridv of life. Such-a cell can safely kloe-used in any sort of equipment without hazard* or damage due to. electrolyte leakage. or'cell disintegration', even-if` thevcelltisv allowed-.to remain in 'the equipment long, after vthe end of Viftsfuseiul life.

-m-y co-.pending` Aapplicatioz-i ySeriali No. 793;406,filed YDecember 28,` 1947, I. have disclosed and 'claimed' an alkaline d-rycell comprisir-ig3 :as gel electrolyte of.v Specialcomposition .and characteristicsV anda novel type^oflanode electrodehaving a Ydisc-shaped honeycomb structure characterized by a high. surface-to-volume ratio.

In my co-pending applications Serial l'SIJs..Y 1295.707 and 32,670, -led February 20,1947 and June 1'2, 1948, respectivel andinm-y co-.pen'ng` applicationSerialllSIay 351,831.,t iled .lune 29`,. 1941i.l now Patent, No.v 2.5545504. dated May. 291,.v "1951,51 have disclosed` and claimed various.- types ofi 'secondary oit-rechargeable cells;

Thefpresent. applicationfis. related tomy aforesaid .Patent No.. 2.422.0155,` andA is a. continuation! in-part of all ofmyl aforesaid co-pendingapplications vand constitutes, an improvement th'ereove'r.

Ain object offthe presentV 'invention is to'filznprove electrochemical cells for "the generati" n and-storage ofv electrical energy, more Aparticularly .tolimprovealkalne dry cells'.

. Other objects and'.` advantages 'will' bei apparent from .the following description and c'lainrs.

`In its broad "aspects,- th'e vpresent 'invention contemplates an. electrochemical..cellfor 'the'gerreration and storage of 'electricall energy. 'such as a. primary or a `seconda'ry' cell; 'comprising'an amalgamated anodefm -the fornr loil-a1'pje'rforat'fed metal. 'disc of Vspecial characteristics; a 'cathode' formed .ofa coherent conductive' biody containing a cathode depolarizergyand an,elel'trol'ytie'.ofv gnlerally solid consistency, for example, one" iff-'the form of a igelf'fo'rmed' of 'anaqli'eou's solutioriof an alkali metal hydroxide, such aszpotassiumshydroxideimmob'ilized' by 'addition ofr a suitalfll'e` gelling agent, such as sodium carboxy-*methyl* cellulose.

In'the drawings:`

Fig. 11is ase'ctional viewofla atdry Centern-.- bodyingfeatures ofthe-'present invention;Y

Fig. 2 is a perspective view of one of the anode elements or discs of the cell shown in Fig. 1; and

Fig. 3 is a sectional View taken on line 3-3 of Fig. 2.

Referring now to the drawing, illustrating an embodiment of the invention into an alkaline primary dry cell, reference numeral I denotes a shallow cup-shaped cathode container or shell formed .of a suitable inert metal, such as steel. Container I0 is provided with an outwardly extending shoulder II beyond which its diameter is slightly enlarged, as this is indicated at I2. Within this container, there is provided' cathode-depolarizer body I3 comprising an electrically conducting electrolytically-reducible oxygen-yielding compound having a smaller quantity of inert material of higher conductivity admixed therewith. The cathode body may be in the form of a prepressed pellet of 95% mercuric oxide and graphite which is inserted into the cathode container and is consolidated therein by a higher pressure so that its exposed surface is substantially ush with shoulder II.

` Anode container I4 is the form of a shallow cup having an outwardly flaring ange I5 at its edge, formed of a metal inert to the electrolyte and having, when amalgamated, a low contact potential with respect to zinc. Examples of suitable materials for the anode container are copper, silver, silver-plated copper, or alloys of copper or silver with other metals. Particularly good results are obtained with anode containers formed of commercial bronze which is an alloy ff ing a temperature of 53 C. and maintaining the f solution therein for ve minutes. After amalgamation, the solution is poured off and the can is washed and dried.

In anode container I4, there are a pair of A amalgamated zinc anode discs I6, having their circumferential edges forcefitted into the container thereby forming with the inner surface thereof a permanent tight fit and an electrical contact of low resistance. Good electrical contact of the anode discs I8 and container I4 is r further Vassured by the amalgam bond formed therebetween upon their assembly.

" As will be best observed in Figs. 2 and 3, the anode discs I6 are in the form of discs punched from suitable anode metal, such'as sheet zinc, and having a large number of small apertures I'I of a polygonal, for example hexagonal shape provided therein. The apertures are so formed that the material removed from the body of the disc is caused to protrude at one side of the disc and to surround the aperture in the configuration of a frustoconical surface I8. Thus, the entire structure could beapproximately described as a plate having a large number of proturberances on one face thereof, and an aperture at the top'of each of said protuberances. Generally speaking, la structure of this type displays a certain similarity to a grater employed in the culinary arts for grating potatoes, cheese, and

the like, and for this reason sometimes will be referred to in the following description and claims as a grater-type anode. While in the illustrated form of this anode all of the protuberances thereof extend in the same direction, itis also possible to have some of them extend in one direction and the remainder thereof exf5" tend in the opposite direction. Considerable variation is also possible in the shape of the apertures which may be square, hexagonal, circular, etc. Likewise, the number of anode discs used in a particular cell may be larger than two or it may be only one.

The novel anode electrodes of the invention provide various important advantages` Thus, as a result of their perforated or foraminous character, they may be in contact with the electrolyte at both faces thereof or may be completely embedded in an immobilized electrolyte body, thereby assuring a high surface-to-volume ratio. This ratio is further improved by the added surface constituted by the protuberances surrounding each aperture. The said protruding portions are also capable of functioning as spacing means which may positively space the anode discs from each other and from the bottom of the anode container. Moreover, the protruding portions greatly increase the mechanical strength of the structure and to a substantial extent compensate for the embrittlement due to amalgamation. Finally the grater-type anode discs may be readily manufactured on a quantity production scale at a low cost.

Anode discs I6 are force-fitted in container I4 so that their protruding apertured portions I8 are downwardly directed whereby they are positively spaced from each other and from the bottom of the container. The container is completely lled out with a body I9 of alkali metal hydroxide electrolyte gel which surrounds and embeds the anode discs and thus fully utilizes their entire surface. The composition and preparation of this electrolyte gel will be more fully described as the description proceeds.

Around the flanged edge I5 of anode container there is stretched a ring or grommet 20 of polystyrene, or some other suitable elastomer, having a downwardly depending cylindrical body portion 2| and an inwardly extending flange portion 22. This ring or grommet, as a result of its novel shape, is capable of performing two different functions. Its body portion 2l is compressed between the cooperating terminal portions of the anode and the cathode containers so that upon radially crimping the cathode container thereon, as indicated at 23, it will provide an airtight seal for the cell. As to its flange portion '22, this extends inwardly to an extent greater than any shrinkage of gel electrolyte body I9 that may occur during the useful life of the cell. As is more fully set forth in my Iaforesaid co-pending application Serial No.

671,200, during operation of cells of the described general type, water is withdrawn from the electrolyte gel body causing it to shrink. Also, as a result of progressive reduction of the depolarizer, particles thereof 'could drop into the interspace between the anode container wall and the shrunken gel electrolyte body, causing detrimental secondary action. This diiculty is particularly serious where the active depolarizer agent is mercurio oxide which is gradually reduced to metallic mercury. This metallic mercury, in the absence of any protective means, would run down into the interspace of anode container and gel body and would short-circuit the cell. All of these diiculties are completely eliminated by the inwardly extending flange portion 22 of sealing grommet 20. f

Preferably, the quantity of zinc in the anode discs I6 is balanced with the depolarizing capacity of the cathode so that both anode or cath- When employing a prefabricatedzgel disc in a cell of the described size in accordance vwith the alternative assembly procedure disclosed in the foregoing, the gel disc had a diameter of 0.970", a thickness of 0.270 and weighed 0.475 gram.

. Although the present invention has been disclosed in connection With a few preferred embodiments thereof, variations and modifications may be resorted to by those skilled in the art without departing from the principles of the invention. Thus, While mercurio oxide is the preferred depolarizer, other depolarizers can be used. Where only very low current densities are needed, such as densities in the order of 10 milliamperes per square inch depolarizer surface, acid precipitated manganese dioxide,- having by Weight of micronized graphite admixed thereto, may be used. Mercuric oxide, however, has the advantage of allowing the application of a Wide range of current densities without polarization, for example, up to 100 milliamperes per square inch depolarizer surface. Y Y

The advantagesof the perforated or gratertype anodes are not restricted to primary cells butare equally apparent in all types of electrochemical cells for `the generation or storage of electrical energy. More particularly, I have obtained good results with anodes of the described character in the secondary or rechargeable cells disclosedand claimed in my aforesaid co-pending applications Serial Nos. 729,707, 32,670 and 35,831.

I consider all of these variations and modifications to be Within the true spirit and scope of thepresent invention, as disclosed in the foregoing description and defined by the appendedclaims.

What is claimed is: f

l. An anode element for electrical current producing cells comprising a plurality of metal plates each having a multiplicity of frustoconical protuberances distributed .over the surface thereof and having an aperture at the top of each of said protuberances, said plates being maintained in parallel-spaced contacting relation by havingr the protuberances of each plate impinging upon the imperforate surface portions of the adjoining plate.

2. An anode element for electrical current producing cells comprising a plurality of metal discs each having a multiplicity of protuberances distributed over and extending from one face thereof and having an aperture at the top of each of said protuberances, the other face of each disc presenting a generally plane and perforate structure, said discs being maintained in parallelspaced superposed relation by having the pretuberances on one face of each disc in pressure contact with the plane face of the adjoining disc.

3. An anode element for primary and secondary cells comprising a plate of zinc having a multiplicity of openings therein, said openings being defined by punctured frusto-conical portions of said plate protuding from the plane of the plate on one face of said plate.

4. An anode element for primary cells comprising an amalgamated plate of zinc having its surface punctured at a multiplicity of points and its material forced out of its plane around each of said points in the same direction thereby constituting a foraminous structure of high surfaceto-volume ratio.

5. An anode element for primary cells comprising an amalgamated zinc disc having a plurality of frusto-conical protuberances extending from only one face thereof, and an aperture at the top of each of said protuberan'ces, said disc having its other face presenting a generally plane perforate appearance and constituting a honeycomb-like foraminous structure of high surfaceto-volume ratio.

6. An anode element for electrical current producing cells constituted by a metal disc having a multiplicity of protuberances distributed over and extending from one face thereof and having an aperture at the top of each of said protuberances, said aperture defining a plane which is substantially parallel with and is spaced from the plane of the disc, the other face of said disc presenting a generally plane and perforate structure.

SAMUEL RUBEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 530,260 De Mott Dec. 4, 1894 764,813 Kamperdyk July 12, 1904 1,087,612 Simmons Feb. 17, 1914 1,138,363 Elmes May 4, 1915 1,436,616 Walsh Nov. 2l, 1922 1,611,153 Benner et al Dec. 21, 1926 1,613,585 Dam Jan. 4, 1927 1,737,130 storey et a1. Nov. 26, 1929 2,154,312 MacCallum Apr. l1, 1939 FOREIGN PATENTS Number Country Date 607,099 Great Britain Aug. 25, 1948 677,424 France Mar. 7, 1930 

1. AN ANODE ELEMENT FOR ELECTRICAL CURRENT PRODUCING CELLS COMPRISING A PLURALITY OF METAL PLATES EACH HAVING A MULTIPLICITY OF FRUSTOCONICAL PROTUBERANCES DISTRIBUTED OVER THE SURFACE THEREOF AND HAVING AN APERTURE AT THE TOP OF EACH OF SAID PROTUBERANCES, SAID PLATES BEING MAINTAINED IN PARALLEL-SPACED CONTACTING RELATION BY HAVING THE PROTUBERANCES OF EACH PLATE IMPINGING UPON THE IMPERFORATE SURFACE PORTION OF THE ADJOINING PLATE. 